<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
        *{
            margin: 0;
            padding: 0;
        }
        html,body{
            width: 100%;
            height: 100%;
        }
        img{
            position: absolute;
            width: 618px;
            height: 128px;
            left: 50%;
            top: 50%;
            margin-left: -309px;
            margin-top: -64px;
            /* 方法二 */
            /* left: 50%;
            top: 50%;
            right: 0;
            bottom: 0;
            margin: auto; */
        }
    </style>
</head>

<body>
    <img src="images/phone.png" alt="手机">
</body>

</html>